Rotary turret selector



Patented July 1, 1947 UNITED STATES PATENT OFFICE ROTARY TURRET SELECTOR Donald R. Mitchell, Chicago, Ill., asslgnor to Galvin Manufacturing Corporation, Chicago, Ill a corporation of Illinois Application November22, 1944, Serial No. 564,676

4 Claims.

This invention relates to a rotary turret for selectively connecting any one of a plurality of electrical circuit elements of like type but different constants in an electric circuit and particularly to a rotary turret selector of the multigang type. While the invention is of general application, it is particularly suitable for use as a selector to connect into the several stages of a high-frequency radio-frequency transmitter or receiver any of various frequency-determining circuit elements to adapt the apparatus to operate at any of a plurality of desired frequencies or frequency bands within a wide frequency range.

Heretofore there have been proposed rotary turrets for selectively connecting inductors, capacitors, resistors or other electrical circuit elements into an electrical circuit. Such devices have the well-known advantage that the lengths and the configurations of the lead-conductors to all of the several circuit elements, as selected, are exactly the same so that the electrical constants oi the circuit with each of the selectable elements connected therein is precisely predetermined. Such an arrangement also facilitates the alignment of a plurality of stages of a multi-band radio-frequency signal-translating circuit including frequency-determining elements selected by such a turret selector.

However the rotary turret selectors of the prior art have been relatively complicated and costly in construction, particularly when constructed in multiple gangs. Among the factors contributing to such complexity and cost have been the accurate spacing and mounting of the rotary elements on the actuating shaft and the accurate alignment of the stationary elements or contacts with the rotary elements or contacts to ensure satisfactory performance. These factors have placed a definite limit on the number of turret elements which could be ganged together for unicontrol operation. The present invention is directed to a rotary turret selector in which either the stationary element or the rotary element is supported solely from the other element and is completely floating and self-aligning.

It is an object of the invention, therefore, to provide a new and improved rotary turret selector which avoids one or more of the above-named disadvantages of the prior art devices.

It is another object of the invention to provide a new and improved rotary turret selector which is simple and economical in construction and one which completely avoids the problem of alignment of the stationary and rotary elements.

It is still another object of the invention to provide a new and improved rotary turret selector of the multi-gang type in which any desired number of turret elements may be ganged together for unicontrol while avoiding the problem of alignment.

In accordance with the invention, a rotary turret element for selectively connecting any one of a plurality of circuit elements of like type but different constants in an electric circuit comprises an outer member or plate having a substantially circular aperture therein and a substantially circular inner member or plate disposed in the aperture, one of the members having a plurality of circuit elements distributed angularly thereon. The turret also includes a plurality of radially extending means disposed about the adjoining periphery of one of the members and extending over opposed faces of the other of the members to retain the inner member within the aperture. The turret also includes means for relatively rotating the inner and outer members and fixed and movable'contact means including a pair of fixed terminals and effective upon relative rotation of the members selectively to connect the circuit elementsto the terminals.

In a preferred form of the invention, the rotary turret element for selectively connecting any of a plurality of circuit elements of the type described comprises a supporting platehaving a substantially circular aperture therein, a substantially circular mounting plate disposed in the aperture and having a plurality of circuit elements distributed angularly thereon and having a central bore therein. The mounting plate is appreciably thicker than the supporting plate and has a diameter appreciably less than that of the aperture to provide a substantial clearance therebetween. The turret also includes a plurality of radially extending contact elements disposed about the periphery of the mounting plate and individually connected to the circuit elements, the contact elements extending over opposite faces of the supporting plate and constituting the sOle means for retaining the mounting plate within the aperture. The turret also includes an actuating shaft extending through the bore of the mounting plate and keyed thereto, the diameter of the shaft being appreciably less than that of the bore to avoid restriction of movementof the inner plate. A pair of terminal contacts is mounted on the supporting plate and is effective, upon relative rotation of the plates selectively to engage the contact elements associated with any one of the circuit elements.

For a better understanding of the invention,

3 together with other. and further objects thereof, reference is had to the following description taken in connection with the accompanying drawings while its scope will be pointed out in the appended claims.

Referring now to the drawings, Fig. 1 is a perspective view of a multi-gang rotary turret selector embodying the invention; Fig. 2 is a view in elevation of one of the rotary turret elements of the structure of Fig. 1; while Fig. 3 is a cross sectional detail through the cooperating contact along the line 3-4 of Fig. 2.

Referring now to Figs. 1 and 2 of the drawings, there is illustrated a gang rotary turret comprising a plurality of turret elements each adapted for selectively connecting any one of a plurality of electrical circuit element of like typ such as inductors, capacitors, resistors, piezo-electric crystals, etc., but of different electrical constants in an electrical circuit. This turret comprises end frames I and II rigidly interconnected by means of through bolts or studs I2, each of which has disposed thereon a plurality of cylindrical spacers or washers I2a for spacing the several turret elements. The construction lends itself to ganging of any desired number of turret elements but by way of illustration there is shown a gang turret comprising nine turret elements as follows: The first turret element II in which the circuit elements selected are piezoelectric crystals Ila; the turrets Il, I5, I6, I1 and I8 in each of which the circuit elements selected are radio-frequency inductors Ila, I5a, Ila, Ila, and I8a, respectively; and the turret elements I9, 20 and 2 I in which the circuit element selected are radio frequency tuning capacitors I9a, 20a and 2Ia, respectively.

Each of the turret elements I3-2I, insofar as the invention is concerned, are identical the differences comprising solely a question of detail in connection with the mounting and connection of circuit contacts of the several circuit elements in accordance with the physical characteristic of the elements. Therefore a detailed description of a single one of the turret elements is sufficient. To this end, there is illustrated in Fig. 2 in detail one of the turret elements, for example the element Il. This turret element comprises an outer stationary supporting plate Ilb, having a substantially circular aperture Ilc formed therein, and a substantially circular inner plate I ld disposed within the aperture Ilc and having a central bore Ilc. One of the plates Ilb, Ild, preferably the latter, comprises a mounting plate having a plurality of circuit elements, in this case the inductors Ila, symmetrically distributed angularly thereon. Preferably, as illustrated, the inductor elements Ila are disposed radially on the mounting plate Ild and project somewhat beyond the outer periphery thereof. Each of the inductors Ila may be secured to the plate Ild in any suitable manner as by rivets or screws Ilf engaging a portion of the inductor elements near the outer periphery of the mounting plate Ild and spring clips Ilg engaging the inner ends of the several inductors I la and secured to the plate Ilcl by pins or rivets Ilh. The supporting plate has notches Ilm in each of two or more corners. for example three as shown, for engaging the mounting bolts I2.

Preferably, the inner mounting plate Ild is appreciably thicker than the outer supporting plate Ill: and has a diameter appreciably less than that of the aperture Ilc in the mounting plate to provide a substantial clearance bet een v 4 the plates Ilb and Ild when the plate Ilb is disposed within the aperture Ilc.

Each of the turret elements also includes radially extending means disposed about the adjoining periphery of one of the plates, for example the mounting plate Ild, and extending over opposite faces of the other of the plates to retain the inner plate Ild within the aperture Ilc, means for relatively rotating the inner and outer plates Ilb and Ild, and fixed and movable contact means including a pair of fixed terminals and effective upon relative rotation of the plates selectively to connect the circuit elements to the fixed terminals. By the term "adjoining periphery is meant either the inner periphery of the outer plate I lb or the outer periphery of the inner plate Ild, which two peripheries adjoin each other. Specifically in the preferred form of the invention, the radially extending retaining means comprises a plurality of radially extending tabs Ili disposed about the periphery of the inner mounting plate Ild, certain or all of these tabs constituting movable contact elements. For example, the tabs Ilt on one side of the plate Ild constitute merely retaining tabs and those on the other side constitute contacts or, as shown, all of the tabs constitute contact elements individually connected in pair to the several circuit elements or inductors Ila.

As more clearly shown in the cross-sectional detail of Fig. 3, the tabs or contact elements Ili extend over opposite faces of the supporting plate Ilb, although, due to the fact that the mounting plate Ild is appreciably thicker than the supporting plate Ilb, the contact elements Ili leave a gap or clearance Ilj on one or both side of the stationary supporting plate Ilb. While as shown in Fig. 3, the inner plate Ild is physically appreciably thicker than outer plate I lb, 0. similar result may be obtained by appropriately offsetting the contact elements Ili so that plate Ild is functionally appreciably thicker than plate Ilb and the term appreciably thicker" is used herein in its generic sense to include these equivalent constructions. These tabs or contact elements constitute in part, or preferably as shown the sole, means for retaining the inner mounting plate Ild within the aperture Ilc.

The turret described also includes means for relatively rotating the inner and outer plates of the several turret elements, specifically, an actuating shaft 22 common to all of the turret elements and extending through the bore of each of the inner mounting plates, such as the mounting plate Ild, and provided with a key-way 22a adapted to engage a key Ilk projecting into the central bore Ile of the mounting plate Ild. The diameter of the shaft 22 is appreciably less than that of the bore Ile to provide a substantial clearance therebetween as shown.

Each of the turret elements also includes at least one and preferably a pair of fixed terminals such as terminals 23 mounted on supporting plate Ilb and effective upon relative rotation of the plates Ilb and Ild selectively to engage the pairs of contact elements associated with any one of the circuit elements or inductors Ila. On the other hand, if only a single fixed terminal contact 23 is provided, the other terminals of the several inductors Ila may be connected to a common terminal or slip ring through which the circuit to each of the inductors may be completed.

The actuating shaft 22 may be operated by any suitable mechanism, there being shown by way of example an operating shaft 2l coupled to the effective selectively to engage the pairs of contact elements I associated with the inductors a with the pair of fixed terminals 23 selectively to include any desired one of the circuit elements, such as the inductor Ma, into circuit therewith, it being understood that the fixed terminals 23 of each of the several turret elements is connected as desired to an external circuit. With this arrangement, it is seen that the lengths of the leadconductors and their configurations remain the same as each of the circuit elements of a turret element is selectively and successively connected into circuit. The result is that the impedances external to the circuit elements themselves remain constant at predetermined values irrespective of which of the circuit elements is switched into position.

It will also be seen that, due to the clearance between the mounting plate Nb and the aperture llc in the supporting plate Nb and due to the clearance I41 between the contact elements iii and the supporting plate Mb, the mounting plate lid is completely floating within the aperture Ho and is retained therein solely by contacts Mi which overlie opposed faces of the supporting plate Nb. At the same time, due to the clearance between the shaft 22 and the central bore Me of the mounting plate lld, the engagement between the shaft and the mounting plate is sufficiently loose that the shaft is effective merely to rotate the inner mounting plate Md and otherwise does not restrict the movement of the plate Md; that is, shaft 22 does not in any way support the mounting plate Nd which rests on or is supported by the supporting plate Nb only. As a result of this complete floating support of the mounting plate Hd, it is entirely self-aligning, that is, it naturally assumes a position such that its contact elements I41 are accurately engaged by the stationary contacts 23. This form of construction eliminates the requirement for accurate and rigid positioning of the mounting disks of the several turret elements on the common actuating shaft 22 and an accurate positioning of the supporting plates of the several turret elements by means of the bolts [2 and spacers I2a since the clearances described are ample to take care of any reasonable manufacturing inaccuracies.

While the invention has been described in connection with a rotary turret selector in which the circuit elements are mounted on an inner freely floating mounting plate surrounded by a supporting plate, it will be obvious to those skilled in the art that the invention is equally applicable to the converse arrangement in which the circuit elements are mounted on the surrounding plates and the terminal contacts on the inner plate. It will also be obvious that, if desired, the inner plates of the turret may be rigidly supported on the actuating shaft l4 and the outer plates given a free floating support from the frame of the device.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be apparent to those skilled in the art that various changes and modiflcations may be made therein without departing from the spirit or scope of the invention.

I claim:

1. A rotary turret element for selectively connecting any one of a plurality of electrical impedance elements of like type but diflerent constants in an electric circuit comprising, an outer plate having a substantially circular aperture therein, a substantially circular inner plate disposed ln said aperture, one of said plates having a plurality of said impedance elements distributed angularly thereon, one of said plates being appreciably thicker than the other and said inner plate having a diameter appreciably less than that of said aperture to provide a substantial clearance therebetween, radially extending means disposed about the adjoining periphery of said one of said plates and extending over opposite faces of the other of said plates to retain said inner plate loosely within said aperture, means for relatively rotating said inner and outer plates, and fixed-and movable contact means including a pair of fixed terminals and effective upon relative rotation of said plates selectively to connect said impedance elements to said terminals.

2. A rotary turret element for selectively connecting any one of. a plurality of electrical impedance elements of like type but different constants in an electric circuit comprising, an outer plate having a substantially circular aperture therein, a substantially circular inner plate disposed in said aperture, one of said plates having a plurality of said impedance elements distributed angularly thereon, a plurality of radially extending contact elements disposed about the adjoining periphery of said one of said plates and individually connected to said impedance elements, means including said contact elements for retaining said inner plate within s'aidaperture, means for relatively rotating said inner and outer plates, and at least one terminal contact effective upon relative rotation of said plates selectively to engage said contact element associated with any one of said impedance elements.

3. A rotary turret element for selectively connectin any one of a plurality of electrical impedance elements of like type but different constants in an electric circuitcomprising, a stationary supporting plate having a substantially circular opening therein, a substantially circular inner plate disposed loosely in said aperture and having a central bore therein, one of said plates having a plurality of said impedance elements distributed angularly thereon, radially extending mean disposed about the adjoining periphery of one of said plates and extending over opposite faces of the other of said plates to retain said inner plate within said aperture, an actuating shaft extending through said bore of said inner plate and keyed thereto, the diameter of said shaft being appreciably less than that of said bore to avoid restriction ofmovement of said inner plate, whereby said inner plate is freely floating in said opening, and fixed and movable contact means including a-pair of fixed terminals and eifective upon relative rotation of said plates selectively to connect said impedance elements to said terminals.

4. A rotary turret element for selectively connecting any one of a plurality of impedance elements of like type but different constants in an electric circuit comprising, a supporting plate having a substantially circular aperture therein, a substantially circular mounting plate disposed in said aperture and having a plurality of said impedance elements distributed angularly thereon'and having a central bore therein, said mounting plate being appreciably thicker than said supporting plate and having a diameter appreciably less than that of said aperture to provide a substantial clearance therebetween, a plurality of radially extending contact elements disposed about the periphery of said mounting plate and individually connected to said impedance elements, said contact elements extending over opposite faces of the supporting plate and constituting the sole means for retaining said mounting plate within said aperture, an actuating shaft extending through the bore of said mounting plate and keyed thereto, the diameter of said shaft being appreciably less than that of said bore to avoid restriction 8 or movement of said inner plate, and a pair of terminal contacts mounted on said supp rtlnl plate and enective upon relative rotation of said plates selectively to engage the contact elements 5 associated with any one of said impedance elements.

DONALD H. MITCHELL.

REFERENCES CITED The following references are of record in the tile of this patent:

UNITED STATES PATENTS Number Name Date 15 2,012,492 Arnold Aug. 13,1935 2,186,950 Allison Jan. 16, 1940 2,177,481 Hall Oct. 24, 1939 

